Labour tried, and failed, over the weekend to persuade the Tories and the Liberal Democrats to put pressure on the main broadcasters to change their election reporting to make it less focused on personalities in the wake of the leaders' election television debates.

A letter drafted by Labour, which called on the BBC, ITV and Channel 4 to devote more time to analysing detailed policy proposals, was rejected on Saturday by both the Tories and the Lib Dems.

The letter was sparked by Gordon Brown's frustration that, while the television debates have sparked great interest in the election, the broadcasters are focusing too much on personalities in the run-up to and aftermath of the Thursday night encounters. The third and final debate, focusing on the economy, will be shown on BBC1 on Thursday night.

Labour wants to focus more on policy issues in the last 10 days of the campaign – and Brown is not considered to have "won" either of the first two debates.

The letter opened by hailing the way in which the debates have given the election a "real sense of energy and excitement". But it added: "As we reach the final stages of the campaign we also share a common belief that the focus on the debates, both the process surrounding them, and the polling before and after which they have attracted, has dramatically reduced the amount of airtime dedicated to the scrutiny of the policies of the parties … We feel that while our manifestos were fully, fairly and properly covered, since then the usual specialist examination of specific policy areas has not been done."

Labour mounted a carefully organised operation to woo their rivals. Benjamin Wegg-Prosser, a former adviser to Lord Mandelson and Tony Blair who has strong links with David Cameron's circle, telephoned the shadow schools secretary Michael Gove. Wegg-Prosser handed the phone to Alastair Campbell who reportedly told Gove that the Lib Dems were interested in the letter. "They were just trying to play us off against each other," one Tory said. Gove reportedly told Campbell and Wegg-Prosser that he thought it was unlikely that the Tories would endorse the letter. But he promised to consult the leadership, which gave its answer today.

A Tory spokesman dismissed Labour's draft letter. "Gordon Brown's desperate whinge to broadcasters to limit their coverage of the TV debates is yet another sign that the wheels have come off his campaign. Thanks to the debates record numbers of viewers have heard more policy discussion than in any previous election.

"Gordon Brown's problem is that when it comes to his ideas the public don't like what they're hearing. He came last in both debates and his party is third in the polls. They are losing on policy substance. If the prime minister wants to inject more substance into the election, inviting Elvis impersonators to take part in his press conferences may not be the way forward."

The Lib Dems responded to Labour, saying: "We have discussed your proposal. However, we do not think that it is appropriate for political parties to seek to dictate the nature of political coverage to broadcasters. We are pleased that because we have set out our policy priorities clearly in our manifesto and included detailed costings, broadcasters and others have been able to analyse our policy and subject it to proper scrutiny and discussion. It might assist coverage if other parties followed suit. We would of course welcome further focus on policy given our clear message, focused priorities and detailed costings."